The present invention relates to a solid composite electrolyte membrane comprising a glass-ceramic composite or a polymer-ceramic composite, and more particularly, to a solid composite electrolyte membrane and a method of making such a membrane for use in lithium ion batteries.
Rechargeable lithium ion batteries are widely used in the art, and generally comprise a lithium anode, a layered insertion cathode, and a membrane which separates the anode and cathode and which contains a lithium ion conducting electrolyte material. Lithium ion batteries currently in use typically employ porous polymeric membranes filled with liquid electrolytes. Liquid electrolytes are typically used because they possess high conductivity; however, the flammability and corrosiveness of such liquid electrolytes severely limit their performance. In addition, such liquid electrolytes often have a short life cycle due to the thermal instability of lithium salt.
While attempts have been made to use solid lithium ion conductors such as single crystals of Li3N and LiI—Li2S—B2S3 glasses, the poor electrochemical stability of Li3N and poor chemical stability of LiI—Li2S—B2S3 glasses have limited the use of these materials in lithium rechargeable batteries. In order to be useful, solid electrolyte membranes must exhibit high ambient temperature conductivity, a large cationic transport number, compatibility with potential electrodes, electrochemical stability, and must be easily processed into useful shapes.
In addition to lithium ion batteries, lithium-air and lithium-water batteries have also been developed. However, the use of these batteries has also been limited by the lack of a chemically stable electrolyte having high conductivity.
Accordingly, there is still a need for a lithium ion conducting electrolyte membrane for use in lithium ion batteries which is not subject to electrochemical instability and which exhibits high conductivity.